There are 3 isoforms of the nonmuscle myosin heavy chain (NMHC), II-A, II-B and II-C. In addition there are four alternatively spliced isoforms of NMHC II-B and II-C. The function of nonmuscle myosin II-C and its isoforms remains unclear. We are expressing the different full length isoforms of nonmuscle myosin II-C (II-C0, NMHC II-C1, and NMHC-II-C2 and NMHC II-C1,C2) in vitro using the baculovirus expression system in order to characterize the full length molecules. In addition we are expressing a mutant II-C isoform known to occur in humans and to cause deafness. We are also generating II-C-GFP transgenic mice, to localize expression of NM II-C in mice in vivo. These experiments will help us understand the function of II-C in both mice and humans.